Maximum demand indicator



Dec. 28, 1948 R. A. TOLLEFSEN ETAL 2,45%286 MAXIMUM DEMAND INDICATOR Filed NOV. 28, 1947 I nvmvroxs REIDAR A. TOLLEFSEIV ROBERT A. HUNT fiTTORNE Y Patented Dec. 28, 1948 MAXIMUM DEMAND INDICATOR Beidar A.

Hunt, Greece, N. Manufacturing Tolleisen, Brighton, and Robert A.

assignors to Rochester Company, Rochester. N. Y., a

corporation of New York Application November 28, 1947, Serial No. 788,748

9 Claims. (Cl. 116129) The present invention relates to dial gauges,

and particularly to dial gauges which have, be-

sides the standard indicating pointer, a maximum pointer to indicate the maximum reading of the gauge. Ina more specific aspect, the invention relates to dial thermometers, and particularly to bi-metailic type dial thermometers which have a maximum pointer to indicate a maximum temperature reading.

Maximum pointers are quite commonly used on pressure gauges, thermometers, and other types of dial gauges. The maximum pointer is operatively connected with the indicating pointer 01 the gauge to move in one direction with the indicating pointer, so as to be carried by the indicating' pointer-to the highest point of movement in one direction of the indicating pointer. The maximum pointer is adapted to stay put at this highest point of reading, when the indicating pointer turns or falls back from that highest point. Thus. the user of the gauge can determine the maximum reading for a given measurement or condition or for a given period- The maximum pointer is adapted to be reset manually to zero when desired.

In gauges of conventional design, the maximum pointer is adapted to be held in the place of maximum reading by friction. This friction must be of sumcient strength to prevent creeping or shifting oi the maximum pointer, even if the gauge is'subjected to vibration. In conventional gauges, the holding means is a coil spring or spring washer and the maximum pointer must be moved by the indicating pointer against the friction exerted by the spring-or spring washer. Such indicating pointer; and this aflects the accuracy of the reading of the gauge.

- One object of the present invention is to proa maximum pointer type gauge in which springs or similar type friction means for holding the .maximum pointer in place are eliminated.

'Another object of the invention is to provide a gauge with a maximum pointer in which the maximum pointer can easily be reset without any frictional drag thereon.

Still another object oi the invention is to provide a gauge with a maximum pointer that is suitable bi-metallic ribbon and may be of conholding means, of course, exert a drag on the sealed against moisture so that it will be possible to use the gauge for outside installations.

= Further objects of the invention are to provide a maximum pointer type gauge which will be simple in construction-and compact and which willbe of increased accuracy.

Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims.

In the drawings;

' Fig. i is a plan view 01 a dial type thermometer made according to one embodiment of this invention;

Fig. 2 isa vertical sectional view through this thermometer; and

Fig. 3 is an exploded view showing the indicating pointer, the maximum pointer, and the parts associated therewith.

The invention has been illustrated in the drawings inconnection with a bi-metallic type dial thermometer. This thermometer comprises the usual casing in, bezel il, graduated dial it, dial retaining ring it, body member ill, bi-metallic element i5, and protector tube It. The bi-metallie element licomprises a helical coil made of a ventional structure. At one end this element may be connected in conventional fashion to an anchoring plug it and at its opposite end to a pointer stem 20. The pointerstem may be journaled in conventional fashion at opposite ends in bearings 2i and 22 which fit into the tube It.

Secured to the upper end of the pointer stem in any suitable or conventional manner is an indicating pointer 25. This indicating pointer may be of conventional design, but has a pin 26 secured thereto near its outer end which serves to engage the maximum pointer as will be described hereinafter. The pin 26 is at one side of the longitudinal center line of the indicating pointer.

The bezel Ii fits over the casing- Hi and serves to hold the glass or crystal 30 against thetops oi the casing and of the spacing ring IS. The crystal may be sealed in place in conventional manner by the gaskets 3| and 32, one of which is interposed between the top of the crystal and the bezel,

and the other of which is interposed between the bottom of the crystal and the tops of the casing and spacing ring.

In the preferred embodiment of the present invention, the crystal 3!! is bored centrally to receive the stem portion 34 of a knurled knob 35. Mounted in a hole in the'lower end of the stem 84 is a pin 36 (Fig. 3) which is preferably made of stainless steel. Mounted on this Pin is a maxi-- a magnetically 3 mum pointer 31 which is made of This pointer attractable metal, preferably steel. has a hole II in it to receive the pin II; and the pin has an enlarged head I! so as to prevent the pointer from falling oi oi the pin. The pin and maximum pointer may be welded or fastened together in any conventional manner.

The portion ll of the stem 34 which extends below the crystal or glass 30 is oi reduced diameter. Fastened to this portion of the stem is a ring which may be made of any suitable permanently magnetized material. A non-metallic washer 4 is interposed between the magnet and the glas It.

In use, the indicating pointer 25 moves with variations in temperature as in a conventional dial thermometer; and as it moves in the direction of higher readings, the pin 2-6 on the pointer 25 engages the maximum pointer 31 carrying the maximum pointer with the indicating pointer, the maximum pointer rotating on its bearing pin 36. When the temperature falls, however, the indicating pointer 25 drops'back to record the temperature at the moment; but the maximum pointer remains at the maximum reading. Such a condition is indicated in Fig. l, where the indicating pointer 25 is recording the temperature at the moment, which is several degrees lower than the highest temperature reached as indicated by maximum pointer 31.

The maximum pointer held in any position, to which it is moved by indicating pointer 25, by the power oi the magnet 40. The magnet is close to the maximum pointer and to increase its holding power, the hub portion 45 or the maximum pointer may be made of enlarged diameter to approximate the diameter of the magnetic ring 40.

While the holding power of the magnet is thus suflicient to retain the maximum pointer in any position to which it may be movedby the indicating pointer, the magnetic attraction exerted by the ring 40 is not enough to create any appreciable drag on the indicating pointer when the indicating pointer is moving in a direction to carry the maximum pointer with it. The magnetic attraction ofthe ring 40 for maximum pointer 31 will not, therefore, afl'ect, beyond the permissible tolerances, the readings of the indi 1 eating pointer. With our construction, then, we

have provided a maximum pointergauge of increased accuracy as compared with prior designs of such gauges.

Since the magnet 40. is fastened to the knurled knob 35, when it is desired to resetthe maximum pointer, all that is necessary is to turn the knob.

The magnet turns with the knob and the maximum pointer follows the magnet by magnetic attraction; and may thus be reset to zero or to any other point desired.

For various purposes, as for outdoor use, it may be desirable to make the thermometer water-' tight. For this purpose, the knob 35 is recessed on its underside; and a rubber washer I6 is mounted in this recess. Thiswasher seats against the upper face oi the glass 30L It is made of sufilcient thickness that, when in place, it will be compressed, between the knurled knob and the crystal. Thus, it will seal against water leaking through the hole in the glass. This washer also prevents breakage of the glass when the magnet 40 is staked to the knob 35.

While the invention has been described in connection with a dial type thermometer, it is obvious that the maximum pointer construction may be applied to any dial type gauge. Thus it scribed may be used on pressure gauges. micrometer gauges, etc. It has been shown in connection with a bi-metallic type thermometer simply for the purposes or illustration and it is to be understood is by no means restricted to such use.

Moreover, while the invention has been described as applied to a maximum pointer gauge it is to be understood that the expression maximum pointer is relative. and that the invention may be used, also, where the recording pointer indicates minimum readings. In this case, of course, the pin 26 will be at the opposite side of the longitudinal center line of the indicating pointer to move the recording pointer 37 with the indicating pointer only when the indicating pglnter moves toward the low end or the scale Furthermore, while the invention has been dein connection with a particular embodiment thereof, it is to be understood that it is capable of further modification, and this applicationiis intended to coverany variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as.come within known or customary practice in the art to which the invention pertains and as may :be applied to the essential features hereinbeforeset forth and as fall within the scope of the invention 'or the limits oi the appended claims.

Having thus described our invention what we claim is: 1. ,A dial gauge having a movable indicating pointer and a recording pointer, means-for moving the recording pointer on movement of the indicating pointer in one direction, and magnetic means for holding the recording pointer in any position to which it. is moved by the indicating pointer. 1 2. A dial gauge having a rotary indicating pointer, a recording pointer tion on an axis aligned with ing the recording pointer in any it may be moved by the indicating pointer.

3. A dial gauge comprising a rotary indicating pointer which is movable in the operation 01' the gauge, a ring made of magnetizedmaterial, and a recording pointer journaled coaxially with'said ring and close to said ring and made of ,a magneticislly attractable material, and means for moving the recording pointer on movement of the indicating pointer in one direction.

4. A dial gauge comprising a ,rotary indicating pointer which is movable in the operation of the gauge, a, supporting member, a recording pointer, which is made of a magnetically attractabie material, journaied on saidsupporting member, means for moving the recording pointerin on'efdirection on movemen -,1. one direction of the indicating to hold the recording pointer in any position to which it may be moved by the indicating pointer.

same, a bearing member mounted in said crystal, an indicating pointer rotatably mounted in the casing, a recording pointer, which is made of a which is journaled on omma magnetically attractable material, journaled on said bearing member interiorly oi the casing, means for moving the recording pointer in one direction on'movement in one direction of the indicating pointer, a knob secured to the bearing member exteriorly oi the crystal to permit rotation the bearing member for moving the recording pointer in the opposite direction, and a magnetic member mounted in the casing coaxial with the pointers and close to the recording pointer to hold the recording pointer in any position to which it may be moved by the indicating pointer.

6. A dial gauge comprising a casing, a crystal mounted on the casing to close one end of the same, a bearing member mounted in said crystal, an indicating pointer rotatably mounted in the casing, a recording pointer having a hub portion the bearing member interiorly o! the casing and which is made of magnetically attractable material, means for moving the recording pointer in one direction on movement in one direction of the indicating pointer, a magnetic ring mounted on the bearing member coaxial with the hub of the recording pointer and close thereto, and a knob secured to the bearing member exteriorly of the crystal for rotating the bearing member.

l. A dial gauge comprising a casing, a crystal mounted on the casing to close one end of the same, abearing member mounted in said crystal, an indicating pointer rotatably mounted in the casing, a recording pointer having a hub portion which is journaled on the bearing member interlorly of the casing above and in axial alignment with the indicating pointer, said recording pointer being made of magnetically attractable material. means secured to the indicating pointer for moving the recording pointer in one direction on movement in one direction of the indicating ter, a magnetic ring mounted on the bearing member coaxial with the hub of the recording 6 pointer and close thereto, a knob secured to the bearing member. eirterioriy of the crystal tor rotating the bearing member, and a flexible sealing member surrounding said bearing member and mounted exterioriy of the crystal between the knob and the crystal to seal the opening in the crystal in which the bearing member is mounted. 8. A dial gauge comprising a casing, a pointer mounted in said casing and movable therein to indicate a measurement, said pointer being made of a magnetically attractable material, a knob journaled in the casing, a magnet secured to said knob close to said pointer, said magnet serving to hold the pointer in any position to which it may be moved in response to a measurement, and said knob being rotatable to move the pointer inde- "pendently of any measuring movement thereof.

9. A dial gauge comprising a casing, a bearing member journaled in said casing, a pointer journaled on said bearing member and rotatable there'- on to indicate a measurement, said pointer being made of a magnetically attractable material, a magnet secured to the bearing member close to the pointer and adapted to hold the pointer in any position to which it may be moved in response to a measurement, and a knob secured to the bearing member exteriorly of the casing to rotate the pointer independently of any measuring movement thereof.

REIDAR'A. TOLLEFSEN. ROBERT A. HUNT.

REFERENCES CITED The following references are of record in the file Of this patent:

UNITED STATES PATENTS 

